retrofit: external vs internal insulation

bartbanis

Edit:

following on from this thread
some posts went off topic so ive dedicated a new thread here

sydthebeat

Internal wall insulation is next on the agenda but current funds will not allow me to do both at once unfortunately. I've been advised internal wall insulation is best suited for my home. Would you think triple glazed windows will make any difference to heat retention without the internal wall insulation in place??

sydthebeat

bartbanis wrote: »

Internal wall insulation is next on the agenda but current funds will not allow me to do both at once unfortunately. I've been advised internal wall insulation is best suited for my home. Would you think triple glazed windows will make any difference to heat retention without the internal wall insulation in place??

depending on your wall construction, its quite possibly your windows will be better insulators than your walls.

why is internal insulation best suited for your house? is it a brick finished house?

BryanF

I'm astonished at the number of homes in my locality that are getting drylining and in 90% of cases I would question its suitability.

bartbanis

Because it is a very old house and there is no cavity in the wall the best solution is to dryline the house, as the walls are so thick. If I were to do it externally the heat would be lost through the wall. Currently it is a very cold house and with the recent winters we are having, money needs to be spent on insulating the house.

sydthebeat

bartbanis wrote: »

Because it is a very old house and there is no cavity in the wall the best solution is to dryline the house, as the walls are so thick. If I were to do it externally the heat would be lost through the wall. Currently it is a very cold house and with the recent winters we are having, money needs to be spent on insulating the house.

If you were to insulate externally you would significantly reduce the heat loss through the walls.

Internal insulation offers nothing that external insulation cant.
Also External insulation covers all those thermal bridges which internal insulation cannot, such as junctions of floors, or where internal masonry walls meet external, at eaves, and even at ground floor as EWI can go right down to foundation level.

Obviously this costs more than the internal insulation, as it is a better solution.

bartbanis

And it does sound better. Originally I wanted to this but people keep advising drylining. There is also the matter of how much space you lose in each room as well as the other points you have noted and you could still occupy the house while external work is in progress. Here's hoping I can raise the money to complete all the work before next winter!!

sydthebeat

bartbanis wrote: »

And it does sound better. Originally I wanted to this but people keep advising drylining. There is also the matter of how much space you lose in each room as well as the other points you have noted and you could still occupy the house while external work is in progress. Here's hoping I can raise the money to complete all the work before next winter!!

what people i wonder?

contractors?

Timmyboy

sydthebeat wrote: »

If you were to insulate externally you would significantly reduce the heat loss through the walls.

Internal insulation offers nothing that external insulation cant.
Also External insulation covers all those thermal bridges which internal insulation cannot, such as junctions of floors, or where internal masonry walls meet external, at eaves, and even at ground floor as EWI can go right down to foundation level.

Obviously this costs more than the internal insulation, as it is a better solution.

Got to disagree with that bit in bold....

- Internal insulation is generally more cost competitive (for the materials and installation labour it seems) in the short term.
- Internal insulation generally leaves you with a finished wall surface on the interior that you can then fit and finish. During a renovation project this can be very significant as you may have needs to refinish both exterior and interior parts but the interior is generally a priority due to the need to inhabit the dwelling. If this is the case then doing exterior insulation provides you with no interior finished surfaces.
- Interior insulation avoids the issue of having too much thermal mass exposed to the internal living environment. Not generally an issue in Ireland in fairness but something to watch out. There can be a significant (generally worthwhile) dampening of temperature changes, but it's not always positive.

BryanF

bartbanis, I strongly recommend you seek a professional independent consultation on your project - preferably from someone who understands moisture movement through old walls, breathable insulation, appropriate ventilation etc etc whether you can afford to the whole project in one go or not take a holistic view of the detailing & specification. your posts so far screams of uneducated salesmen spinning you yarns.

bartbanis wrote: »

I've been advised internal wall insulation is best suited for my home.

as pwe syd's request: please tell WHO advised you of this? especially as you go on to suggest:

bartbanis wrote: »

it is a very old house

please read around this forum and some of the previous threads on why old buildings require different methods of insulation etc etc may7be search under 'old stone walls', 'dampness in walls' or 'breathable wall'

and there is no cavity in the wall the best solution is to dryline the house, as the walls are so thick.

incorrect, who advised you of this? if you dryline - you risk interstitial condensation issues (read http://www.josephlittlearchitects.com/documents/Breaking_the_Mould_1_Construct_Ireland_Issue_6_Vol_4.pdf )

If I were to do it externally the heat would be lost through the wall.

do you intend to live in this house on a daily basis? if so then thermal mass is your friend

now for this gem

Timmyboy wrote: »

Got to disagree with that bit in bold....
((Internal insulation offers nothing that external insulation cant.))
- Internal insulation is generally more cost competitive (for the materials and installation labour it seems) in the short term.

what? in the short term? what kind of caveat is that? yes its cheaper but its not as comprehensive as EWI as it doesnt cover internal wall junctions, overlap with the floors/ ceiling/ eaves etc

- Internal insulation generally leaves you with a finished wall surface on the interior that you can then fit and finish.During a renovation project this can be very significant as you may have needs to refinish both exterior and interior parts but the interior is generally a priority due to the need to inhabit the dwelling.

significant? so the point your making is that most renovations require fresh internal plastering and therefore dry-lining is a cheaper option? surely this is the same as your first point..

If this is the case then doing exterior insulation provides you with no interior finished surfaces.

the same cost point, again.

- Interior insulation avoids the issue of having too much thermal mass exposed to the internal living environment.

WHAT? whats wrong with thermal mass? and then you stick in a caveat which makes no sense:

Not generally an issue in Ireland in fairness but something to watch out.

watch out? please elaborate further?

There can be a significant (generally worthwhile) dampening of temperature changes, but it's not always positive.

what?

this is an old house, there is no cavity, it may not even be conventional concrete blocks and mortar. to summarise your post: dry-lining is cheap - yes it is, but its a half baked solution especially in this scenario.

Timmyboy

BryanF wrote: »

now for this gem
what?

I'm responding to a rather massive wholistic statement earlier that basically suggests a one way outcome, i.e. external insulation because QUOTE "Internal insulation offers nothing that external insulation cant"
Generally there's always more than one solution for everything.
I don't accept and I think most people agree that where it has been said one option "offers nothing" that the other can't. That just is not true and is patently misleading.
Not with most things in this world, and most certainly not with construction activities.

BryanF wrote: »

in the short term?

In the short term means during the year ahead and one or two years

BryanF wrote: »

what kind of caveat is that?

It means that in these financially constrained times, where some people are trying to make do with what they have available that the cheaper option is sometimes the only option in the short term.
Ideally if there is more opportunity for expenditure then external insulation may be a better outcome in many cases, but not all.

BryanF wrote: »

yes its cheaper

It's good to see we agree on my earlier point!;)

BryanF wrote: »

but its not as comprehensive as EWI as it doesnt cover internal wall junctions, overlap with the floors/ ceiling/ eaves etc significant?

I agree that the dry-lining situation is generally not as comprehensive. Significant risks with damp entrapment around cold junctions is a big big issue.
Massive attention to detail is required. More so than with external insulation.
This was never part of the reasons that I put forward.

BryanF wrote: »

so the point your making is that most renovations require fresh internal plastering and therefore dry-lining is a cheaper option? surely this is the same as your first point..
the same cost point, again. WHAT?

More or less, yes. I repeated it twice, not deliberately but I was trying to provide better explanation than I had earlier given.

BryanF wrote: »

whats wrong with thermal mass? and then you stick in a caveat which makes no sense: watch out? please elaborate further?what?

OK, here's one realistic practical example.
Family lives in house. Leaves house to visit relatives during a cold spell.
Comes back to house and the heating has been off during the days while away. House is cold.
Due to the insulation being on the outside their is a slower internal air temperature response due to the heat being absorbed by the full thermal mass of the buidling, whereas with dry-lining there is less heat absorbed during that warm-up period since mainly the major thermal impact is from the mass of the dry-lining, which is an insulator and is close to the habitable rooms.
:rolleyes:

BryanF wrote: »

this is an old house, there is no cavity, it may not even be conventional concrete blocks and mortar. to summarise your post: dry-lining is cheap - yes it is,

Cost is important. But let's give a few other reasons too,
Exgternal appearance.
Difficulty of application in cold or inclement weather.
Need for erection of scaffolding etc (time delays additional to the extra cost)

BryanF wrote: »

but its a half baked solution especially in this scenario.

The biggest half bakers are generally those solutions which are rapidly adopted by some as being the only, final solutions. Lots of people hop on a band wagon and go with it. Same way as many architects/engineers/quantity surveyors hopped on the construction bandwaggon and with the banks and the government led the country astray along with other vested interests.

I've no vested interest here but I will not and cannot accept statements that are made that are use conslusive words like "nothing". I've been listening to too much of that type of attitude from dreamers in the Irish Construction Industry for too long to know a sardine when I see it.

There's always more than one way.

Other ways can work in certain situations with careful attention to detail.

sydthebeat

Timmy, you are simply incorrect.

i stand over my comment that internal insulation offers nothing that external insulation cannot.

1. just because internal wall insulation (IWI) is a cheaper solution does not mean that, apropo, it can offer something that EWI cannot. Its cheaper because its worse.

2. Internal finishes. Your grasping at straws if you think one of the 'selling points' of IWI is a smoother internal finish Conversely one of the advantage sof EWI is a more traditional, or exposed brick / stone internal finish.

3 thermal mass. It is generally considered by the industry that a higher thermal mass is preferable than lower. Low TM houses that heat up quickly, cool off quicker. Thermal mass helps regulate the temperature internally significantly better than low thermal mass. refer to any DEAP or PHPP assessment for the affects of thermal mass.

im not going to get into a huge debate here because the merits of both have been debated many times over in this forum. It is the consensus, after this debating, that IWI should only be considered as a realistic solution in applications where EWI is(a) not possible or (b) not practical from planning or heritage reasons. ie in brick terrace applications, listed buildings etc.

EWI is more expensive because it is a better solution.

Timmyboy

Just one other reason why EWI may not be always the suitable option. It's kind of a Heritage type reason but I don't want the actual description of that to hide behind the general bland reasoning of "Heritage".

Certain older houses have rafters butting onto the top of the single leaf solid wall. Then above that are the slating battens and then the slates which rest along the edge of the stone/masonry/concrete etc. outer edge of the single leaf solid wall.

There is a detail issue here for EWI, which although there are solutions is another expensive piece of work involving full removal of typicall the last 2 layers of slate and re-arrangemnet of slates on new extensions of the rafters etc. along with other solutions. Certainly not a cheap solution and not a simple one either especially if the roof is part of a dormer/storey and a half type construction etc.



"EWI is more expensive because it is a better solution. "

We should know better by now that that's not always the case!
Not certainly in Ireland and not certainly when dealing with construction or construction products.

I'll point out to people here that there is a major amount of profiteering going on with EWI.

I do recognize the merits of EWI instead of IWI. But there are many things to consider and that's why I've pointed out reasons here that people may or may not have been made aware of in the 'debates' so far.
It's important that people know as much as they can.

My points remain for themselves intact.

It is generally never correct to state the everything is just so because...

(Note that I used the word "generally":D)

bartbanis

Two things guys, yes I am very new to all this and trying to pick up as much as possible as qiuck as I can and I appreciate all the advice I can get and secondly I will be seeking a professional independent consultant on these issues but it would be great to have some idea of what he is talking about when he calls!!
Its a project that I dont think I can just look for cheapest option, I would spend twice as much just to make sure I was getting the right work done. With each house being different I know until consultant calls its hard to say what is best for me.
Appreciate all help thanks
Bart

Robierto

Currently renovating a 1950s bungalow.
the builder is begging me to let him do internal insulation, but I'm holding tough! We've had to slash other budgets though to make sure we can externally insulate sooner rather than later.
However I need a shot of reassurance on two things:

1. Cold bridges at foundations: is it worth paying (thousands?) more to dig down a foot to put insulation down to foundations? And doesn't the heat travel down anyway?
2. We have pebbledash walls currently. Are we going to have to have to replaster before attaching the insulation to prevent problems associated with these gaps?!?

All sounding very expensive..

BryanF

Robierto wrote: »

Currently renovating a 1950s bungalow.
the builder is begging me to let him do internal insulation, but I'm holding tough! We've had to slash other budgets though to make sure we can externally insulate sooner rather than later.
However I need a shot of reassurance on two things:

1. Cold bridges at foundations: is it worth paying (thousands?) more to dig down a foot to put insulation down to foundations? And doesn't the heat travel down anyway?
2. We have pebbledash walls currently. Are we going to have to have to replaster before attaching the insulation to prevent problems associated with these gaps?!?

All sounding very expensive..

1. in order to avoid a large (say 300mmm linear) thermal bridge from the rising wall, good practice dictates that the insulation is taken to the foundation level. If in doubt get a thermal analysis done.
2. I've had reassurances from several of the better European manufacturers that once the insulation is sealed at all perimeters to the wall (pebble dashed or not) the existing external render can be left alone. IMO this question comes down to: what company you are going with, who is applying it and who is overseeing the job is done correctly

manana

Is it possible to externally insulate at the back only due to old red brick facade?

gerry1958

I am looking to retrofit insulation to a 1930s semi detached house. The front of the house is of a particular type (part brick and otherwise for planning reasons cannot be altered with EWI). However the gable end and the rear of the house are suitable for EWI. Is it possible to apply IWI to the front walls and EWI to the gable and rear? Are there any issues arising.
Thanks for all replies.

househero

gerry1958 wrote: »

I am looking to retrofit insulation to a 1930s semi detached house. The front of the house is of a particular type (part brick and otherwise for planning reasons cannot be altered with EWI). However the gable end and the rear of the house are suitable for EWI. Is it possible to apply IWI to the front walls and EWI to the gable and rear? Are there any issues arising.
Thanks for all replies.

Start a new thread gerry

Outkast_IRE

househero wrote: »

Start a new thread gerry

he did it got closed for some reason

BryanF

Sorry wrong way round, new thread open now